High-purity aluminum oxide or alumina powder can be used to make translucent tubes for high-pressure sodium lamps, sapphires for watch covers, high-strength ceramic tools, abrasives for magnetic tape, light emitting diodes as a substrate for GaN, silicon microchip wafers for optic-electronics, windows and cowls for aircrafts, protective windows for car headlamps, cell phones and other electronic devices, stop signals, surgery scalpels, micro-optical elements of medical fiber-optic probes, optical scanners for bar codes, ultraviolet CD and DVD optical systems, prisms, lenses, optical plates, optical systems of visual and IR diapasons, cell phone, mobile devices and fiber-optic system display windows, equipment for chemical manufacturing in aggressive and high-temperature environments: tubes, crucibles, funnels, chemical glassware, abrasives, battery components, bearings and jewelry stones.
Currently the most common methods of making high-purity alumina for manufacturing Sapphire for LED substrates are aluminum-ammonium-sulfate thermal decomposition, aluminum-ammonium-carbonate thermal decomposition and aluminum-isopropoxide hydrolyzation. The high-purity alumina is then used in the Verneuil process to make crackle or compressed into densified pucks, granules or beads for melting in a sapphire ingot furnace.
Previous work in the field of alumina purification used aluminum trihydrate, bauxite, gibbsite, aluminum oxides, or ores containing aluminum oxide as the starting raw material for the process.